Equilibrium and rate constants for the following types of protonic reactions are being obtained in the gas phase utilizing ion cyclotron resonance spectroscopy: A1H plus plus A2 reversible yields A2H plus plus A1, A1H plus B plus A2 reversible yields A2H plus B plus A1, AH plus B1 plus B2 reversible yields AH plus B2 plus B1. The work involves basic mollcules, i.e., A, A1, A2, B, B1, B2, which contain functional groups of biological importance. Emphasis is placed upon conjugate acids of pyridine derivatives as well as cations of the OH , NH, SH and PH ions types. It is proposed to develop a "solvent" molecule which models quantitatively in the gas phase certain roles of the aqueous medium. Hydrogen-bond affinities of bases for gaseous cationic proton donors will be compared with pKHB parameters for a critical series of bases. F-nmr shielding parameters for appropriately substituted fluorobenzenes are being utilized in sensitive studies of pure medium effects. A quantitative separation of "nonspecific" polar medium effects and hydrogen-bonding medium effects has been proposed. Critical tests of the treatment will be made.